1. Field
A photoluminescent layered composite, a backlight unit, and a display device including the composite are disclosed.
2. Description of the Related Art
Liquid crystal display (“LCD”) devices form an image with external light, unlike plasma display panels (“PDPs”) and field emission displays (“FEDs”), which form an image using self-emitting light. The light for LCD devices is provided by a backlight unit on the rear side. As for the backlight unit for an LCD device, a cold cathode fluorescent lamp (“CCFL”) has been used as a light source. However, the CCFL used as a light source does not provide uniform luminance and a color purity of the CCFL deteriorates when the LCD device has a larger screen. As a result, a backlight unit using three-color LEDs as a light source has been recently developed. Since the backlight unit using the three color LEDs as the light source produces improved color purity, as compared to the backlight unit using the CCFL, it is used in a high quality display devices. However, the backlight unit using three color LEDs as a light source costs more than the backlight unit using the CCFL as a light source. To mitigate this problem, a white LED that emits light by converting light output from a single color LED chip to white light has been proposed. However, although the white LED is not as expensive as the three-color LEDs, color purity and color reproducibility of the white LED are less than a color purity and color reproducibility of an LCD device including the three-color LEDs. Accordingly, various attempts to develop a quantum dot-containing light conversion layer material, and a backlight unit and a display device including the same and having improved cost competitiveness as well as improving color purity and color reproducibility, have been made.